A Study on the Fretting Wear Resistance of a Zirconium Alloy with the Variation of Supporting Spring Properties

An effort has been made in the present investigation to evaluate the wear resistance of nuclear fuel rods with a variation of the supporting spring shapes and their stiffness by conducting fretting wear tests in room temperature air and water. With increasing slip amplitude, the wear volume and maximum wear depth are increased with increasing slip amplitude. However, these are not linearly increased with increasing spring stiffness. After the wear test, the worn surfaces were observed to investigate the debris behavior and wear mechanism by using an optical microscope (OM). The results indicated that almost all of the wear debris remained between the contacting surfaces and the wear debris layers were well developed in room temperature air. Besides, some of the debris also remained on the worn surface in room temperature water. This result shows that the remaining debris effect on the worn surface was more dominant than the spring stiffness one. So, in order to improve the fretting wear resistance of a nuclear fuel rod, it is necessary to consider the debris behavior between contacting surfaces even though the supporting spring shape was optimized by considering the contact mechanics, material compatibility, etc. From the experimental results, the fretting wear mechanisms and the effect of spring properties were discussed.